Cam box for flat knitting machines



June 2, 1970 Filed Feb. 2. 1968 P. JOSEPH 3,514,976

CAM BOX FOR ,FLAT KNITTING MACHINES 2 Sheets-Sheet 1 b 120: 1 1 26 v, 33 12 23/: a 2 d um 1 mm 2 1a 1 I ll llllllll mm mm. mmmfif .7! 7 *3 f n mmmmm I? 1, I b mw mlmlllmuu a I I. y M :5

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INVENTOR.

PIERRE (JOSEPH /9 'TOREE 5 June 2, 1970 v JOSEPH 3,514,976

CAMBOX FOR FLAT KNITTING MACHINES Filed Feb. 2, 1968 2 Sheets-Sheet 2 Fig. 3

INVENTOR. PIE/QPE dosE H United States Patent Int. c1. D04b 7/04 US. Cl. 6678 4 Claims ABSTRACT OF THE DISCLOSURE A flat knitting machine comprises two needle beds which are inclined one relative to the other in the shape of an inverted V and having knitting members such as needles and pushers connected to the needles, said knitting members being each provided with two butts cooperating'with the cams of at least one cam box for each needle bed. The cam box comprises cams having working faces for cooperation with the butts of the knitting members. Groups of two opposite working faces on two cams act together on the butts of the knitting members to positively control the knitting members in all regions of the cam box where the knitting members have to affect a longitudinal movement. The arrangement of the cams is such that at the end of one working face acting on one of the two butts begins another working face oriented in the same direction as the previous working face and acting on the other butt.

This invention relates to cam boxes for a flat knitting machine of the kind having two opposite needle beds inclined relatively to one another like an inverted V, equipped with knitting members having two butts per member.

A few years ago, the wool yarns had been the most used for the fabrication of knitted articles. A critical speed of knitting was empirically determined, which speed, considering the strength of the yarns, allowed to work with an admissible rupture ratio of the yarns. Since several years, the hosiery works use synthetic yarns in increasing amounts. Knowing that the resistance to rupture of these yarns, at even fineness is greatly increased, the knitting speeds also were increased. It was then rapidly remarked that the needles did barely endure a considerable increase of this speed, the hooks and even the butts often broke owing to fatigue after a few thousand movements.

Endurance tests have proved that the principal reasons for premature breaking of the hooks and butts were, for an important proportion, the sudden acceleration of the needles at the beginning of the lifting movement, when the butts strike against the lifting cam, and to another, also important proportion, the shocks at the places of the junctions of the different cams A device for avoiding such sudden accelerations is described in the present assignees Swiss patent application No. 15,243/66.

In the knitting technique junction is understood to designate the small step and/or the small pit which are formed between two cam working faces situated on two adjacent cams. The dimensions of the pit are additionally increased by the bevels or roundings provided at the intersections of the faces defining each cam.

When said tests were made, it was ascertained that the movements imparted to the knitting members, such as for example the lifting movement, are superposed by zig-zag movements of an amplitude equal to the clearance between the working faces and the butts. Owing 'ice to this second movement the butts frequently hit against the pit and receive a shock in a direction opposite to the movement imposed by the cams.

The present invention accordingly relates to a cam box which avoids said second mentioned principal source of rupture of the needles, namely the shocks due to the junctions between the different cams of a cam box by avoiding the junctions.

A principal object of the invention is the provision of a cam box for knitting machines of the above mentioned type, in which the presence of junctions between adjacent cams is avoided.

The cam box of this invention cooperates with the knitting members having two butts per member. These members can be needles having two butts, or pushers having two butts, attached to needles without butts; the use of needles having one butt, attached to pushers having one butt would not be convenient, because it would complicate the Jacquard selection.

Such knitting members are known since long ago. They are used e.g. in certain Jacquard knitting machines. The cam boxes of these machines are provided with two channels displaced one relative to the other in the direction of the movement of the carriage, so that each channel has a well determined function, and that each knitting member cooperates with a single butt of the cam box at one and the same time (German Pats. 19,510; 22,361, 71,227).

The German Pat. 1,132,678 describes the use of needles having two butts and an adequate form of cam box in a circular knitting machine, for the purpose of avoiding irregular movements of the needles in case of rupture of the working butt, and for the purpose of providing a member for detecting the rupture of said butts.

The French Pat. 1,096,173 describes the use of needles having two butts and an adequate form of cam box in a circular knitting machine for the purpose of avoiding the needles provided for the sinking point lift to continue their lifting movement owing to their throw to such a high position that the loop passes behind the latch and a new loop is formed instead of a tuck loop.

The cited patents accordingly have not the same object as the present invention, namely the suppression of shocks due to the junctions between the different cams.

The cam box according to the invention comprises the provision of cams provided with working faces and entrance faces, the working faces of the cams being arranged in groups of two opposed working faces to positively control the butts of said knitting members in all regions of the cam box in which said members have to effect a movement imposed by said cams in longitudinal direction of said members, said two working faces of a group acting together on the butts of said members, and being so arranged that at the end of a working face of one cam acting on one of said two butts begins a correspondingly oriented working face of another cam acting on the other butt of the knitting member, and the end of each working face of a cam being followed by an entrance face of the cam gradually retreating towards the interior of the cam with respect to the movement path of the butts at the end of said working face.

Two embodiments of cam boxes according to the invention are described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a section according to the line 1-1 of FIG. 2 and represents two needle beds equipped with knitting members having two butts each for cooperation with the cams of the cam boxes;

FIG. 2 is a diagrammatic view of the cam assembly on the face of a cam plate for a knitting machine without stitch transfer;

FIG. 3 is a diagrammatic view of the cam assemblies on the faces of the two cam plates for a knitting machine with stitch transfer.

Each of the two needle beds shown in FIG. 1 is provided in known manner with grooves 3, each of which is equipped with a knitting member. In this example the knitting member is composed of a needle 2 attached by a spherical joint 4 to a pusher 5. This latter carries two butts 6 and 7 which cooperate with a cam box. The grooves 3 are deepened by notches 8 permitting one to sink the pushers into the needle bed in such manner, that the butts do no longer project beyond the upper face 9 of the needle bed and are no longer actuated by the cams of the cam box. The pushers to be sunk can be selected by a known Jacquard-mechanism not represented.

The rear butts 7 can be of varying height for increasing the patterning possibilities of the knitting machines.

The cam box which is designated as a whole by 10, will be explained later. In FIG. 1 a cam plate 11 carries a plurality of cams. The butt 6 of a pusher penetrates into a channel formed between the working faces 1211a and 21a of two cams 12 and 21. The butt 7 also penetrates between the cams, but does not contact the working faces at the location of the section I-I.

Certain cams can be sunk or made to collapse by means of known and not represented mechanisms. These mechanisms usually are fixed to the cam plate 11 on the face opposite to that carrying the cams.

FIG. 2 shows the arrangement of the cams on the cam plates of the cam box for a knitting machine without stitch transfer. The carriage (not shown) which carries at least one such cam box effects a to-and-fro movement. In the figure, the cam box is moved from the left to the right and the relative position of the cams is drawn correspondingly. The front butts 6 first encounter the upper alignment cam 12 the working face 12a of which is on the usual alignment level of the butts. This level is determined by the position of the butts, when the needle hooks are substantially aligned with the comb 13 (FIG. 1). The lower alignment cam 14 with its working face 14a is situated in front of this cam. The two working faces 12a and 14a are preceded, on the side of the entry of the butts 6, by entrance faces 12b and 14b. These two faces form a funnel narrowing to the width of the channel 15 formed between the faces 12a and 14a. This funnel serves to align the butts 6 which would not be at their usual level. The channel 15 serves to stabilize the knitting members which would not be at the said level. At the outlet of the channel 15 the butts 6 bear against the face 12a. Ahead of the point 120 marking the end of this face 12a, there begins the entrance face 17b of an acceleration cam 17. The two faces 12a and 17b form a second funnel. This latter could seem to be unnecessary, but upon a stop of the machine at the interior of the field of needles, particularly when the needles do not carry any loops, it is not excluded that they slide in the groove, their butt 6 abandoning the face 12a. The said funnel therefore has the purpose of collecting and of realigning the needles.

A knocking-over cam 16 is situated in front of the acceleration cam 17. These two cams are fixed on a common guide block 18 which can slide in a slot 19 of the cam plate 11. Due to being fixed to the common block, the distance between these two cams is invariable. A working face 16a formed on a knocking-over cam 16 begins in substantially vertical alignment with the end 12c of the working face 12a. The face 12d which follows the face 12a after the point 120, constitutes the entrance face for the working face 12ml of the cam 12. It gradually retreats towards the interior of the cam 12 with respect to the path of the butts 6. The faces 12aa and 16:: have the same orientation at this location and are parallel between themselves.

The point 120 is aligned with the beginning of the working face 1611. At this point the knitting members will start to eflfect a lifting movement in the direction of their length. The butts 7 are positively guided between the working faces 16a and 17a. The beginning of the face 17a is parallel to the face 12a. The distance between these two faces is slightly greater than the distance L in FIG. 1, thus providing a clearance between the working faces and the butts which bear thereon. At those places where the knitting members are controlled by two opposite faces, as for example in FIG. 3 by the faces 32a and 32m, the distance between these faces must be smaller than the distance l of FIG. 1. Owing to absence of junctions in the zones where movements are imposed by the working faces of the earns, the clearance between these faces and the butts can be greater than in conventional cam boxes and can vary from one place to another, without being detrimental to the object to be obtained. For the same reason it is not necessary to determine the exact location of the end or of the beginning of two consecutive faces. Thel beginning of one working face is the place where the butts begin to make contact with the entrance face in their zigzag movement which is superposed to the imposed movements.

These same considerations can be applied to all beginnings of working faces in the zones where movements are imposed by the cams.

It is obvious that the indifference to variable and great clearances considerably decreases the cost of mounting or of replacing the cams.

The face 17a is curved from its beginning in such manner, that the knitting members are subjected to a gentle and gradual acceleration. The end of the curve 17a is followed by a lower lifting face 20a and this latter is followed by an entrance face 201) which gradually retreats towards the interior of the cam with respect to the path of the butts 7.

The conventional raising cam 21 in the described example serves only to finish the lower lifting movement of the needles and to maintain them at their sinking point. The entrance faces 21b are gradually retreating towards the interior of the cam 21 with respect to the path of the butts 6, for example by having a steeper slope than that of the lifting path of the butts. The working face 12aa of the alignment cam 12 serves as guard face. Following the end of the entrance face 12d the butts 6 bear against the face 12m, and the butts 7 bear against the end of the lifting face 2021. At the place where the butts 7 abandon this face there begins the working face 21a. This latter, and the face 12aa, together gradually brake the knitting members while bringing them to the sinking point.

The central cam 22 is movable in the direction at right angles to the surface 9 of the needle bed 1. It can be positioned into at least three positions, namely: position working where it drives all butts which emerge from the surface of the needle bed; half position where it drives only the high butts, and the position out of wor or sunk in the plate 11 where it can no longer drivingly engage the butts. The knitting members having the butts out of driving engagement with the cam 22 effect tucking of the loops and those of which the butts are driven, form loops. The manner of guiding, as well as the control mechanisms of such cams, are known and not represented. This cam Which is symmetrical with respect to the axis A-A, contains two entrance faces 22b gradually retreating towards the interior of the cam with respect to the path of the butts and to a working face 2211. This latter accelerates gradually the butts 7. The respective butts 6 bear against the face 12aa, until the point 1200. At this point the butts 6 abandon the cam 12 and the lifting is braked on the butts 7 by a guard face 21aa provided in the cam 21, this face being again preceded by an entrance face 21bb gradually retreating towards the interior of its cam with respect to the path of the butts.

The knockover movement of the knitting members is controlled in an analogous manner on the other side of the cam box with respect to the center line AA, and

the movements which differ from the lifting movements, will be described. Beyond the point 230 of the upper alignment cam 23 the butts 6 are no longer guided; however, the butts 7 are taken over by the working face 24a of the knocking over cam 24; they are guided at the same time by the working face 25a of the acceleration cam 25. The two faces 24a, 25a are preceded by their entrances faces 24b, 25b, respectively, which gradually retreat towards the interior of their cams.

The cams 24 and 25 are fixed to a guide block 26 slidably mounted in a slot 27 of the cam plate The position of the cams 24, 25 and block 26, particularly that of the nose 24n, determines the length of the formed loop. The curved accelerating face of the cam'25 is situated in front of the nose and operates here as a sinking stop, and owing to this fact, it adjusts the length of the loops. The lower alignment cam 28 with its face 28a loosens the loops by acting on the butts 6 to push the knitting members to their usual level. The channel 29 serves to stabilise them at this level.

The low butts 7 of the knitting members which effect tucking of the loops are not driven by the central cam 22 (which is shown in the above-mentioned half position) and due to this fact, they pass along a straight line, the corresponding butts 6 bearing on the right hand portion of the face 21a of the cam 21. Since they do not effect any movement during this time, and since they were stabilized by the channel 30, it is not necessary to positively guide them.

The upper alignment cam 23, just as the cam 12, carries an entrance face 23kb, retreating towards the interior of its cam, and followed by the faces 23aa, 23d, 23a, and 23b similar to the corresponding faces already described for the cam 12.

FIG. 3 shows the cam boxes for a knitting machine with stitch transfer. Besides the central portion already described, there are two transfer cams 31, 34 and 32, 33, respectively on each carn box. During knitting, these cams are sunk. For the transfer of loops the two transfer cams which follow the lower alignment cams, as seen in the direction of travel of the carriage, are put into operation and the knitting cams 16, 17, 21, 22, 24 and 25 are sunk. During a transfer, for example the transfer cams 31 and 32 will operate. The butts 6 on both needle beds are aligned by the fixed cams 23, 23 and 28, 28' and stabilised in the channels 29, 29'. The junction 35 between the cams 28 and 32, as well as the junction 36 between the cams 28 and 31 cannot be detrimental to the knitting members because these latter are stabilised and at rest, during the passage of these junctions. The knitting members of the front needle bed are positively controlled by the working faces 32a and 32aa during their movement. Those of the rear needle bed are controlled by the working faces 31a and 31aa. In the example, the loops are transferred from the needles of the rear needle bed to the needles of the front needle bed.

I claim:

1. A cam box with cams for a flat knitting machine having two opposed needle beds which are inclined one relative to the other in inverted V-shape and equipped with knitting members, each knitting member having two butts, cams having working faces which collaborate with the butts, the working faces being arranged in groups of two opposed working faces to positively control the butts of said knitting members in all regions of the cam box in which said members are to effect a longitudinal movement imposed by said cams, said two working faces of a group forming together a movement path for the butts of said members, wherein the improvement comprises, at least at one end of the working face of each cam the provision of another working face on another cam, whose beginning is correspondingly oriented and at a distance corresponding to the distance of correspondingly oriented faces of said butts, and of an entrance face gradually projecting from the interior of said other cam toward the movement path of the butts and having its end adjacent to said beginning on a level with said beginning.

2. A cam box according to claim 1, in which junctions are present between the cams at such places where working faces are perpendicular to said knitting members.

3. A cam box according to claim 2, in which each junction is preceded by a channel perpendicular to said knitting members.

4. A cam box according to claim 1, in which a varying clearance is provided between the butts of the knitting members and the working faces acting on said butts.

References Cited UNITED STATES PATENTS 2,116,761 5/1938 Korber 6675 3,304,748 2/ 1967 Seiler 66-6 X FOREIGN PATENTS 628,624 2/ 1969 Germany. 407,290 5/ 1934 Great Britain.

RONALD FELDBAUM, Primary Examiner 

